The present invention relates generally to a novel thermophilic aspartase, a process for the production thereof, microorganisms capable of producing the enzyme and a process for producing L-aspartic acid using the enzyme.
L-aspartic acid is an important amino acid and is useful as a drug for recuperation from fatigue, an antidote against ammonia, a food additive or a diagnostic agent.
Heretofore, L-aspartic acid has been commercially produced by fermenting a microorganism such as Escherichia coli (Japanese Patent Publication No. 6588/63). Additional methods for the production of L-aspartic acid using immobilized cells have also been reported [Samejima and Kimura: Enzyme Engineering 2 131, Plenum Press, New York and London, (1974), Tosa and Chibata: Applied Microbiology Vol. 27, 886, (1974)].
While the aforementioned methods provide commercially acceptable yields of the product, it would be advantageous in the prevention of contamination, acceleration of enzymatic reaction, saving of energy and the like to carry out the fermentation procedures, enzymatic reactions, etc. at a high temperature.
To this end, after studying the aspartase activity of various thermophilic bacteria it has now been found that thermophilic bacteria of the genus Bacillus produce thermophilic aspartase which can readily be used for the production of L-aspartic acid in a high temperature environment.